Minnesota has become a battleground in a presidential campaign that has dramatically tightened nationwide.

A new Star Tribune Minnesota Poll shows that the race is now a dead heat between Barack Obama and John McCain, each supported by 45 percent of likely voters in the state.

The new poll likely will stoke both sides' efforts during the final 51 days until the election, triggering a barrage of advertising, grass-roots politicking and, potentially, stepped-up visits by the candidates.

The poll found that McCain has made gains across the board since a May Minnesota Poll that showed him trailing by 13 points. He has picked up considerable support among men and to a lesser degree among women. He also has boosted his standing with whites, young voters and all levels of household income and education.

Conducted a week after the Republican National Convention was held in St. Paul, the poll likely reflects -- at least in part -- the traditional bounce candidates enjoy after being in the spotlight.

Part of the rise in McCain's fortunes nationally has been attributed to his choice of Alaska Gov. Sarah Palin as his running mate, a move that has energized his party's conservative base.

But the Minnesota Poll found that the choice of Palin was essentially a wash among the state's voters.

While 30 percent said it made them more likely to vote for the Republican ticket, 26 percent said it made them less likely to do so. For the rest, it didn't make much difference.

Strong reactions to Palin

Follow-up interviews with people who participated in the poll, however, showed that Palin evokes strong reactions.

"I think she's a good choice," said McCain supporter Paul Harling, 51, a welder from Silver Bay. "Anyone who can manage a family and a job and do well at both can probably run the government better than the Washington bureaucrats who are in there now."

Linda Estrem, 50, who works in payroll for an insurance firm in Owatonna, said she doesn't believe Palin "has proven she's qualified. I listen to her talk, and I don't want to see her as president of the United States. And I don't agree with the reason I think he put her on the ticket, which was to pull in the female vote."

The poll found that men are slightly more likely than women to say the choice of Palin boosted their support for McCain.

Democratic vice presidential candidate Joseph Biden is seen as far more qualified to be president than Palin, even though Minnesotans have a less favorable opinion of him.

The state's voters are evenly divided as to whether Palin is qualified to become president, with 43 percent agreeing that she is and 45 percent saying she isn't.

Sixty-six percent say Biden is qualified, while 20 percent disagree.

Paradoxically, Palin's overall favorable rating is slightly higher than Biden's, 53 percent for her to 46 percent for him.

The poll contains a bright spot for Obama -- his support among likely voters is more solid than McCain's. Seventy percent of those supporting the Obama-Biden ticket describe their support as strong, compared with the 59 percent of McCain-Palin backers.

Jeff Blodgett, Obama's Minnesota state director, reacted to the poll results "the way we react to any other poll -- we've always known the race was going to be close here all along."

Golnik and Blodgett said their campaigns will continue to rely on statewide door-knocking and their phone banks during the final weeks of the campaign, focusing on undecided voters. Golnik said either McCain or Palin probably will visit the state in the next two weeks.

Questions of age, experience

Two underlying tensions of the campaign -- McCain's age and Obama's relative lack of experience -- appear to pose problems for the respective candidates.

"If something happens to him, the next in line is Palin and she doesn't have enough experience to be vice president, much less president," Donovan said.

Forty-four percent say Obama is too inexperienced to be an effective president.

"I think McCain is a little more seasoned, a little more experienced than Obama," said McCain supporter Jamie Bergeland, 38, an office manager from Centerville. "Obama stands for a lot of good things and has some great ideas, but at this point, McCain has more life experience and leadership going into this election."

At the same time, Obama fares far better than McCain when those polled try to assess whether he "understands the needs and problems of people like you." Sixty-three percent agree with that statement when it's applied to Obama, compared with 47 percent who say that about McCain.

But McCain is ahead of Obama, 67 percent to 54 percent, when Minnesotans were asked whether the candidates would be effective as commander in chief.

On handling domestic issues, including the economy, health care and gasoline prices, Obama fares considerably better than McCain; McCain fares better than Obama on the issues of the war in Iraq, terrorism and national security.

"For the first time, I have a politician I agree with on every single point, whether it's the economy, health care, alternative energy," said Obama supporter Cathy Lundquist, 47, a homemaker from Wheaton. "He lines square up with me -- and McCain doesn't even talk about the issues. He's just talking bad about Obama."

Said McCain backer Brian Jensen, 57, a chemical engineer from Edina, his candidate "has tons more experience and lines up with me on the issues. I don't want to jack up social spending the way Obama would. ... And I think we need to stay in Iraq until everything's stabilized, the way McCain wants to."

The poll results reinforce some of the candidates' perceived strengths, even as they confound others.

White evangelicals, who account for nearly a quarter of likely voters, overwhelmingly favor McCain, while he has an edge among a similar number who identify themselves as white Catholics. But among other whites -- half of those polled -- Obama enjoys a slight lead.

Despite the widespread belief that Obama is overwhelming popular among young voters, he and McCain are essentially tied with voters younger than 35.

U.S. stocks are opening higher Friday morning as major indexes continue to set records. Technology companies are rising on company earnings. Health care and household goods companies also trading higher after lagging the market over the last few weeks.